A civil war soon broke out, most prominently between two major contending powers – Xiang Yu and Liu Bang, who were respectively the rulers of the Chu and Han kingdoms.

The war ended with a Han victory at the Battle of Gaixia in 202 BCE, during which Xiang Yu committed suicide after having made a last stand.

After Xiang Yu took control of Xianyang, he allowed his troops to pillage and plunder the city and ordered the destruction of the Epang Palace.

Later, Xiang Yu forced Liu Bang to relocate from Guanzhong to the remote, underdeveloped Bashu region (present-day Chongqing and Sichuan).

In 206 BCE, after the former Qin Empire was divided into the Eighteen Kingdoms, Liu Bang was made King of Han and relocated to the Bashu region (present-day Chongqing and Sichuan) along with 30,000 troops and thousands of civilians.

Zhang Er, the former King of Changshan, joined Liu Bang after losing his domain to Zhao Xie and Chen Yu.

In September–October 205 BCE, the Chu capital, Pengcheng (彭城; present-day Xuzhou, Jiangsu), fell to a coalition force led by Liu Bang.

Liu Bang was caught off guard and his army suffered heavy casualties and his family members were captured by Chu forces.

Upon reaching Xiayi (下邑; east of present-day Dangshan County, Anhui) which was guarded by his brother-in-law, Liu Bang reorganised his troops for a retreat.

Meanwhile, Han Xin led reinforcements from Guanzhong into central China and defeated a Chu army between Jing County (京縣) and Suo Village (索亭), both in present-day Henan.

[1] He also put down a rebellion by Wang Wu and Cheng Chu – former Qin generals – and Shen Tu, the magistrate of Wei, and captured their base at Waihuang (外黃; in present-day Minquan County, Henan).

Han Xin also developed his plan to conquer northern China, with the aim that Xiang Yu would be too distracted by Liu Bang and his bases of Xingyang and Chenggao to properly counter Han Xin in the north, nor could he endanger his line of retreat by marching past Xingyang and Chenggao into Guanzhong.

In November 205 BCE, after Han Xin's victory at the Battle of Jingxing, Ying Bu agreed to join Liu Bang and rebelled against Xiang Yu.

On another front, Ying Bu was unable to resist Long Ju's attacks so he gave up on his domain in Jiujiang and joined Liu Bang.

In 205 BCE, Wei Bao left Liu Bang on the pretext of visiting an ill relative and secretly returned to his domain.

Xiang Yu constantly sent his forces to attack the Kingdom of Zhao, but Han Xin and Zhang Er managed to hold their ground.

Meanwhile, Tian Guang had decided to surrender to Liu Bang so he had pulled back his forces from Lixia (歷下; present-day Jinan, Shandong).

On the night before the battle, Han Xin sent his men to dam the Wei River (濰水; in present-day Weifang, Shandong) with sandbags.

The next morning, after a skirmish with Chu forces, Han Xin feigned defeat and retreated to lure the enemy to follow him.

Long Ju was killed in action and the rest of the Chu forces disintegrated as Han Xin continued pressing the attack.

Tian Guang fled while Han Xin pursued the retreating Chu forces to Chengyang (城陽; near present-day Ju County, Shandong).

At the same time, Xiang Yu felt worried after losing Long Ju, so he sent Wu She to incite Han Xin to rebel against Liu Bang and declare himself king.

Xiang Yu changed his mind, pressed the attack on Xingyang and besieged Liu Bang's forces inside the city.

Liu Bang's forces conquered Chenggao and defeated the Chu army led by Cao Jiu near the Si River.

Following Han Xin's victory at the Battle of Wei River, the Chu forces' morale fell and they ran short of supplies months later.

Xiang Yu and Liu Bang then agreed to a ceasefire at the Treaty of Hong Canal, which divided China into east and west under the Chu and Han domains respectively.

However, as Han Xin and Peng Yue did not mobilise their troops, Liu Bang was defeated by Xiang Yu at Guling (固陵; south of present-day Taikang County, Henan) and forced to retreat and reinforce his defences.

At the same time, he sent messengers to Han Xin and Peng Yue again, promising them land and titles if they joined him in attacking Xiang Yu.

Xiang Yu attempted to break out the siege and was left with only 28 men when he reached the northern bank of the Wu River (烏江; near present-day He County, Anhui).

He made a last stand and managed to slay hundreds of Han soldiers before he was eventually overwhelmed and ended up committing suicide by slitting his throat.